Inflammation Flashcards
what are the features of inflammation?
- a non-specific response to cellular injury
- a universal process in health and disease
what are the four main signs of acute inflammation and how do they occur?
1) Redness (Rubor) - accumulation of RBCs
2) Heat (Calor) - incr. presence of fluid at core body temp at site + high metabolic rate of immune cells
3) Swelling (Tumor) - incr. blood flow into inflamed tissues = fluid build-up
4) Pain (Dolor) - mediators signal nerve cells
5) Loss of function (Functio laesa)
What is acute inflammation?
rapid response non-specific response to cellular injury
What happens as there is damage in acute inflammation?
1) inflammatory signals released i.e. to non-apoptotic cell death/foreign material\
2) vasodilators - nitric acid + histamine
3) vascular endothelium cause change - vasodilation, plasma leak, incr. permeability, reduce flow of blood.
Describe histamine
sources
actions
mast cells, basophils, platelets
vasodilation, incr. vascular permeability, endothelial activation
Describe prostaglandins
sources
actions
mast cells, leukocytes
vasodilation, pain, fever
Describe cytokines (TNF, IL-1)
sources
action
mast cells, macrophages, endothelial cells
Endothelial activation (adhesion molecules), fever, malaise, pain, anorexia, shock
Describe chemokines
sources
actions
Leukocytes, activated macrophages
Chemotaxis, leukocyte activation
Describe complement (C5a, C3a, C4a)
sources
actions
Plasma (produced in the liver)
Leukocyte chemotaxis and activation, vasodilation (mast cell stimulation), opsonisation
What is exudate?
Fluid, proteins and cells that have seeped out of a blood vessel
What is immune cell recruitment?
-Recruitment and inflammation signals at the site of manage e.g. chorines produced
What happens during neutrophil extravasation?
1) chemo-attraction e.g. cytokines
2) rolling adhesion
3) tight adhesion
4) transmigration
What is the function of a neutrophil at sight of inflammation?
1) Pathogen recognition
2) Pathogen clearance - netosis + phagocytosis
3) cytokine secretion -recruitment of other immune cells
What is the resolution of acute inflammation?
1) Pathogen recognition
2) mediators and neutrophils have short half life - turned over rapidly
3) macrophages - clear apoptotic cells + anti-inflammatory mediators
4) repair + wound healing
What are the reasons for chronic inflammation?
occurs as a result of a failure in acute inflammation to clear the danger signals:
-Persistent inflammatory stimulii i.e. persistant infection
What are the good and bad parts of macrophages?
good:
1) macrophages can be recruited as monocytes and they differentiated in situ
2) Phagocytic
3) Cytotoxic
4) Anti-inflammatory
5) Wound repair
bad:
1) cytotoxins can affect tissues → not very selective
2) pro-fibrotic → promotes wound healing → too much extracellular matrix → scar
What are T cell lymphocytes role in inflammation?
1) pro-inflammatory
2) cytotoxic - but selective as they don’t kill surrounding tissues
3) Regulatory
What are B cell lymphocytes role in inflammation?
1) Generate plasma cells that secrete antibody.
2) Protective, clearing infection
Inflammatory, driving reactions against self
3) Can either be local to inflammatory site, or operate remotely
(base of all vaccines)
What is granulomatous inflammation?
Chronic inflammation with distinct pattern of granuloma formation
- Triggered by strong T cell responses
- t-cells aggregate and fuse around the area
What are the features of acute inflammation?
-Immediate onset; lasts a few days
-Vasodilation, increased vascular permeability, leukocyte response
-Neutrophils predominate
-Histamine release
-Prominent necrosis
-Outcomes include:
Complete resolution
Progression to Chronic Inflammation
What are the features of chronic inflammation?
-Delayed onset; may last weeks, months or years
-Persistent inflammation, ongoing tissue injury, attempts at healing
-Monocytes / Macrophages predominate
-Ongoing cytokine release
-Prominent scarring
-Outcomes include:
Scarring
Loss of function
What are the possible positive outcomes of acute and chronic inflammation?
- Clear inflammatory agent.
- Remove damaged cells
- Restore normal tissue function
What are the possible negative outcomes of acute and chronic inflammation?
- Excess tissue damage
- Scarring
- Loss of organ function → organ failure
What does wound healing lead to?
extracellular matrix deposition
What are the consequences of inflammation?
- Broncho-pneumonia
- Wound healing in sensitive tissues
- Scarring
